MECHANICS AND USEFUL ARTS. 87 



buts, and small tubes run from this to each but, and, in long trees, to 

 holes about the centre, thus expediting the impregnation. The junc- 

 tion of the tube with the tree is carefully packed with a piece of cloth. 

 The liquid advances through the tree at about the rate of one metre in 

 twenty hours. The drip after passing through the wood is nearly 

 colorless. A saw-cut around the tree to the depth of the sap-wood, 

 with a piece of cotton cord tied in it, carries off the drip from any 

 part above it. This is led back to the reservoir, to be again used with 

 new material. President's Message, Part 1. 



At the Isle of Portland, England, where an immense breakwater is 

 at present building, the numerous driving piles are impregnated with 

 creosote, which is injected in the proportion of Ik gallons to the cubic 

 foot, by a pressure of 160 pounds to the square inch. Editors. 



USE OF THE GASES ESCAPING FROM BLAST-FURNACES. 



AT the recent meeting of the British Association at Edinburgh, 

 Mr. Palmer Budd detailed his mode of applying the gases escaping 

 from blast-furnaces. He said it was well known that there are two 

 descriptions of furnaces used for metallurgic purposes. The one is 

 the blast-furnace, into which air is injected by mechanical means, at a 

 great density, so as to penetrate upwards of forty feet of dense materi- 

 als ; and the other is the reverberatory furnace, where the fire is pro- 

 duced by means of the draft of a chimney-stack. What he had ac- 

 complished is by combining these two, so that the gaseous products of 

 the furnace, instead of escaping through the funnel-head, are drawn 

 sideways by a high stack, and, passing through the stoves and boilers, 

 leave behind the necessary temperature of the blast and of the steam. 

 In a blast-furnace the ores are smelted before the tuyeres, by the con- 

 version of the solid carbon into carbonic acid, which, passing up 

 through the middle region of the furnace into a bath of carbon, is re- 

 converted into carbonic oxide, capable of combining with a farther dose 

 of oxygen. It would be thus seen that the whole of the carbon of the 

 fuel should be present at the top of the furnace in a gaseous form. 

 Experience had proved that, by the aid of a stack, at the end of the 

 chain, of sufficient dimensions, the gaseous escape from the furnace 

 may be made to travel in the most tortuous directions, descending to 

 the stoves built for heating by the usual fire-places, and traversing the 

 boilers, the only condition absolutely necessary being that there should 

 be an unbroken communication with the high stack at the end, into 

 which the gaseous escape may at last pass, and by which it is drawn 

 forward, instead of passing off wastefully at the funnel-head. When, 

 however, the draft is carried downward, and to long distances, he had 

 found it necessary to drop into the top of the furnace a hopper or fun- 

 nel, made of sheet-iron, which acts as a shield at. the mouths of the 

 horizontal flues, and prevents them from either being affected by high 

 winds, or from being choked up by materials thrown into the furnace. 

 The reason, no doubt, why this funnel was not applied before, was 

 the great apparent temperature at the funnel-head. In practice, how- 

 ever, it is found, that, until the gaseous escape mingles with the at- 



